LCOV - code coverage report
Current view: top level - src/backend/main - main.c (source / functions) Hit Total Coverage
Test: PostgreSQL 17beta1 Lines: 42 102 41.2 %
Date: 2024-06-14 19:10:57 Functions: 4 6 66.7 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * main.c
       4             :  *    Stub main() routine for the postgres executable.
       5             :  *
       6             :  * This does some essential startup tasks for any incarnation of postgres
       7             :  * (postmaster, standalone backend, standalone bootstrap process, or a
       8             :  * separately exec'd child of a postmaster) and then dispatches to the
       9             :  * proper FooMain() routine for the incarnation.
      10             :  *
      11             :  *
      12             :  * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
      13             :  * Portions Copyright (c) 1994, Regents of the University of California
      14             :  *
      15             :  *
      16             :  * IDENTIFICATION
      17             :  *    src/backend/main/main.c
      18             :  *
      19             :  *-------------------------------------------------------------------------
      20             :  */
      21             : #include "postgres.h"
      22             : 
      23             : #include <unistd.h>
      24             : 
      25             : #if defined(WIN32)
      26             : #include <crtdbg.h>
      27             : #endif
      28             : 
      29             : #if defined(__NetBSD__)
      30             : #include <sys/param.h>
      31             : #endif
      32             : 
      33             : #include "bootstrap/bootstrap.h"
      34             : #include "common/username.h"
      35             : #include "port/atomics.h"
      36             : #include "postmaster/postmaster.h"
      37             : #include "tcop/tcopprot.h"
      38             : #include "utils/help_config.h"
      39             : #include "utils/memutils.h"
      40             : #include "utils/pg_locale.h"
      41             : #include "utils/ps_status.h"
      42             : 
      43             : 
      44             : const char *progname;
      45             : static bool reached_main = false;
      46             : 
      47             : 
      48             : static void startup_hacks(const char *progname);
      49             : static void init_locale(const char *categoryname, int category, const char *locale);
      50             : static void help(const char *progname);
      51             : static void check_root(const char *progname);
      52             : 
      53             : 
      54             : /*
      55             :  * Any Postgres server process begins execution here.
      56             :  */
      57             : int
      58        3078 : main(int argc, char *argv[])
      59             : {
      60        3078 :     bool        do_check_root = true;
      61             : 
      62        3078 :     reached_main = true;
      63             : 
      64             :     /*
      65             :      * If supported on the current platform, set up a handler to be called if
      66             :      * the backend/postmaster crashes with a fatal signal or exception.
      67             :      */
      68             : #if defined(WIN32)
      69             :     pgwin32_install_crashdump_handler();
      70             : #endif
      71             : 
      72        3078 :     progname = get_progname(argv[0]);
      73             : 
      74             :     /*
      75             :      * Platform-specific startup hacks
      76             :      */
      77        3078 :     startup_hacks(progname);
      78             : 
      79             :     /*
      80             :      * Remember the physical location of the initially given argv[] array for
      81             :      * possible use by ps display.  On some platforms, the argv[] storage must
      82             :      * be overwritten in order to set the process title for ps. In such cases
      83             :      * save_ps_display_args makes and returns a new copy of the argv[] array.
      84             :      *
      85             :      * save_ps_display_args may also move the environment strings to make
      86             :      * extra room. Therefore this should be done as early as possible during
      87             :      * startup, to avoid entanglements with code that might save a getenv()
      88             :      * result pointer.
      89             :      */
      90        3078 :     argv = save_ps_display_args(argc, argv);
      91             : 
      92             :     /*
      93             :      * Fire up essential subsystems: error and memory management
      94             :      *
      95             :      * Code after this point is allowed to use elog/ereport, though
      96             :      * localization of messages may not work right away, and messages won't go
      97             :      * anywhere but stderr until GUC settings get loaded.
      98             :      */
      99        3078 :     MemoryContextInit();
     100             : 
     101             :     /*
     102             :      * Set up locale information
     103             :      */
     104        3078 :     set_pglocale_pgservice(argv[0], PG_TEXTDOMAIN("postgres"));
     105             : 
     106             :     /*
     107             :      * In the postmaster, absorb the environment values for LC_COLLATE and
     108             :      * LC_CTYPE.  Individual backends will change these later to settings
     109             :      * taken from pg_database, but the postmaster cannot do that.  If we leave
     110             :      * these set to "C" then message localization might not work well in the
     111             :      * postmaster.
     112             :      */
     113        3078 :     init_locale("LC_COLLATE", LC_COLLATE, "");
     114        3078 :     init_locale("LC_CTYPE", LC_CTYPE, "");
     115             : 
     116             :     /*
     117             :      * LC_MESSAGES will get set later during GUC option processing, but we set
     118             :      * it here to allow startup error messages to be localized.
     119             :      */
     120             : #ifdef LC_MESSAGES
     121        3078 :     init_locale("LC_MESSAGES", LC_MESSAGES, "");
     122             : #endif
     123             : 
     124             :     /*
     125             :      * We keep these set to "C" always, except transiently in pg_locale.c; see
     126             :      * that file for explanations.
     127             :      */
     128        3078 :     init_locale("LC_MONETARY", LC_MONETARY, "C");
     129        3078 :     init_locale("LC_NUMERIC", LC_NUMERIC, "C");
     130        3078 :     init_locale("LC_TIME", LC_TIME, "C");
     131             : 
     132             :     /*
     133             :      * Now that we have absorbed as much as we wish to from the locale
     134             :      * environment, remove any LC_ALL setting, so that the environment
     135             :      * variables installed by pg_perm_setlocale have force.
     136             :      */
     137        3078 :     unsetenv("LC_ALL");
     138             : 
     139             :     /*
     140             :      * Catch standard options before doing much else, in particular before we
     141             :      * insist on not being root.
     142             :      */
     143        3078 :     if (argc > 1)
     144             :     {
     145        3078 :         if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
     146             :         {
     147           0 :             help(progname);
     148           0 :             exit(0);
     149             :         }
     150        3078 :         if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
     151             :         {
     152        1248 :             fputs(PG_BACKEND_VERSIONSTR, stdout);
     153        1248 :             exit(0);
     154             :         }
     155             : 
     156             :         /*
     157             :          * In addition to the above, we allow "--describe-config" and "-C var"
     158             :          * to be called by root.  This is reasonably safe since these are
     159             :          * read-only activities.  The -C case is important because pg_ctl may
     160             :          * try to invoke it while still holding administrator privileges on
     161             :          * Windows.  Note that while -C can normally be in any argv position,
     162             :          * if you want to bypass the root check you must put it first.  This
     163             :          * reduces the risk that we might misinterpret some other mode's -C
     164             :          * switch as being the postmaster/postgres one.
     165             :          */
     166        1830 :         if (strcmp(argv[1], "--describe-config") == 0)
     167           0 :             do_check_root = false;
     168        1830 :         else if (argc > 2 && strcmp(argv[1], "-C") == 0)
     169           0 :             do_check_root = false;
     170             :     }
     171             : 
     172             :     /*
     173             :      * Make sure we are not running as root, unless it's safe for the selected
     174             :      * option.
     175             :      */
     176        1830 :     if (do_check_root)
     177        1830 :         check_root(progname);
     178             : 
     179             :     /*
     180             :      * Dispatch to one of various subprograms depending on first argument.
     181             :      */
     182             : 
     183        1830 :     if (argc > 1 && strcmp(argv[1], "--check") == 0)
     184         208 :         BootstrapModeMain(argc, argv, true);
     185        1622 :     else if (argc > 1 && strcmp(argv[1], "--boot") == 0)
     186          82 :         BootstrapModeMain(argc, argv, false);
     187             : #ifdef EXEC_BACKEND
     188             :     else if (argc > 1 && strncmp(argv[1], "--fork", 6) == 0)
     189             :         SubPostmasterMain(argc, argv);
     190             : #endif
     191        1540 :     else if (argc > 1 && strcmp(argv[1], "--describe-config") == 0)
     192           0 :         GucInfoMain();
     193        1540 :     else if (argc > 1 && strcmp(argv[1], "--single") == 0)
     194         102 :         PostgresSingleUserMain(argc, argv,
     195         102 :                                strdup(get_user_name_or_exit(progname)));
     196             :     else
     197        1438 :         PostmasterMain(argc, argv);
     198             :     /* the functions above should not return */
     199             :     abort();
     200             : }
     201             : 
     202             : 
     203             : 
     204             : /*
     205             :  * Place platform-specific startup hacks here.  This is the right
     206             :  * place to put code that must be executed early in the launch of any new
     207             :  * server process.  Note that this code will NOT be executed when a backend
     208             :  * or sub-bootstrap process is forked, unless we are in a fork/exec
     209             :  * environment (ie EXEC_BACKEND is defined).
     210             :  *
     211             :  * XXX The need for code here is proof that the platform in question
     212             :  * is too brain-dead to provide a standard C execution environment
     213             :  * without help.  Avoid adding more here, if you can.
     214             :  */
     215             : static void
     216        3078 : startup_hacks(const char *progname)
     217             : {
     218             :     /*
     219             :      * Windows-specific execution environment hacking.
     220             :      */
     221             : #ifdef WIN32
     222             :     {
     223             :         WSADATA     wsaData;
     224             :         int         err;
     225             : 
     226             :         /* Make output streams unbuffered by default */
     227             :         setvbuf(stdout, NULL, _IONBF, 0);
     228             :         setvbuf(stderr, NULL, _IONBF, 0);
     229             : 
     230             :         /* Prepare Winsock */
     231             :         err = WSAStartup(MAKEWORD(2, 2), &wsaData);
     232             :         if (err != 0)
     233             :         {
     234             :             write_stderr("%s: WSAStartup failed: %d\n",
     235             :                          progname, err);
     236             :             exit(1);
     237             :         }
     238             : 
     239             :         /*
     240             :          * By default abort() only generates a crash-dump in *non* debug
     241             :          * builds. As our Assert() / ExceptionalCondition() uses abort(),
     242             :          * leaving the default in place would make debugging harder.
     243             :          *
     244             :          * MINGW's own C runtime doesn't have _set_abort_behavior(). When
     245             :          * targeting Microsoft's UCRT with mingw, it never links to the debug
     246             :          * version of the library and thus doesn't need the call to
     247             :          * _set_abort_behavior() either.
     248             :          */
     249             : #if !defined(__MINGW32__) && !defined(__MINGW64__)
     250             :         _set_abort_behavior(_CALL_REPORTFAULT | _WRITE_ABORT_MSG,
     251             :                             _CALL_REPORTFAULT | _WRITE_ABORT_MSG);
     252             : #endif                          /* !defined(__MINGW32__) &&
     253             :                                  * !defined(__MINGW64__) */
     254             : 
     255             :         /*
     256             :          * SEM_FAILCRITICALERRORS causes more errors to be reported to
     257             :          * callers.
     258             :          *
     259             :          * We used to also specify SEM_NOGPFAULTERRORBOX, but that prevents
     260             :          * windows crash reporting from working. Which includes registered
     261             :          * just-in-time debuggers, making it unnecessarily hard to debug
     262             :          * problems on windows. Now we try to disable sources of popups
     263             :          * separately below (note that SEM_NOGPFAULTERRORBOX did not actually
     264             :          * prevent all sources of such popups).
     265             :          */
     266             :         SetErrorMode(SEM_FAILCRITICALERRORS);
     267             : 
     268             :         /*
     269             :          * Show errors on stderr instead of popup box (note this doesn't
     270             :          * affect errors originating in the C runtime, see below).
     271             :          */
     272             :         _set_error_mode(_OUT_TO_STDERR);
     273             : 
     274             :         /*
     275             :          * In DEBUG builds, errors, including assertions, C runtime errors are
     276             :          * reported via _CrtDbgReport. By default such errors are displayed
     277             :          * with a popup (even with NOGPFAULTERRORBOX), preventing forward
     278             :          * progress. Instead report such errors stderr (and the debugger).
     279             :          * This is C runtime specific and thus the above incantations aren't
     280             :          * sufficient to suppress these popups.
     281             :          */
     282             :         _CrtSetReportMode(_CRT_ERROR, _CRTDBG_MODE_FILE | _CRTDBG_MODE_DEBUG);
     283             :         _CrtSetReportFile(_CRT_ERROR, _CRTDBG_FILE_STDERR);
     284             :         _CrtSetReportMode(_CRT_ASSERT, _CRTDBG_MODE_FILE | _CRTDBG_MODE_DEBUG);
     285             :         _CrtSetReportFile(_CRT_ASSERT, _CRTDBG_FILE_STDERR);
     286             :         _CrtSetReportMode(_CRT_WARN, _CRTDBG_MODE_FILE | _CRTDBG_MODE_DEBUG);
     287             :         _CrtSetReportFile(_CRT_WARN, _CRTDBG_FILE_STDERR);
     288             :     }
     289             : #endif                          /* WIN32 */
     290        3078 : }
     291             : 
     292             : 
     293             : /*
     294             :  * Make the initial permanent setting for a locale category.  If that fails,
     295             :  * perhaps due to LC_foo=invalid in the environment, use locale C.  If even
     296             :  * that fails, perhaps due to out-of-memory, the entire startup fails with it.
     297             :  * When this returns, we are guaranteed to have a setting for the given
     298             :  * category's environment variable.
     299             :  */
     300             : static void
     301       18468 : init_locale(const char *categoryname, int category, const char *locale)
     302             : {
     303       18468 :     if (pg_perm_setlocale(category, locale) == NULL &&
     304           0 :         pg_perm_setlocale(category, "C") == NULL)
     305           0 :         elog(FATAL, "could not adopt \"%s\" locale nor C locale for %s",
     306             :              locale, categoryname);
     307       18468 : }
     308             : 
     309             : 
     310             : 
     311             : /*
     312             :  * Help display should match the options accepted by PostmasterMain()
     313             :  * and PostgresMain().
     314             :  *
     315             :  * XXX On Windows, non-ASCII localizations of these messages only display
     316             :  * correctly if the console output code page covers the necessary characters.
     317             :  * Messages emitted in write_console() do not exhibit this problem.
     318             :  */
     319             : static void
     320           0 : help(const char *progname)
     321             : {
     322           0 :     printf(_("%s is the PostgreSQL server.\n\n"), progname);
     323           0 :     printf(_("Usage:\n  %s [OPTION]...\n\n"), progname);
     324           0 :     printf(_("Options:\n"));
     325           0 :     printf(_("  -B NBUFFERS        number of shared buffers\n"));
     326           0 :     printf(_("  -c NAME=VALUE      set run-time parameter\n"));
     327           0 :     printf(_("  -C NAME            print value of run-time parameter, then exit\n"));
     328           0 :     printf(_("  -d 1-5             debugging level\n"));
     329           0 :     printf(_("  -D DATADIR         database directory\n"));
     330           0 :     printf(_("  -e                 use European date input format (DMY)\n"));
     331           0 :     printf(_("  -F                 turn fsync off\n"));
     332           0 :     printf(_("  -h HOSTNAME        host name or IP address to listen on\n"));
     333           0 :     printf(_("  -i                 enable TCP/IP connections (deprecated)\n"));
     334           0 :     printf(_("  -k DIRECTORY       Unix-domain socket location\n"));
     335             : #ifdef USE_SSL
     336           0 :     printf(_("  -l                 enable SSL connections\n"));
     337             : #endif
     338           0 :     printf(_("  -N MAX-CONNECT     maximum number of allowed connections\n"));
     339           0 :     printf(_("  -p PORT            port number to listen on\n"));
     340           0 :     printf(_("  -s                 show statistics after each query\n"));
     341           0 :     printf(_("  -S WORK-MEM        set amount of memory for sorts (in kB)\n"));
     342           0 :     printf(_("  -V, --version      output version information, then exit\n"));
     343           0 :     printf(_("  --NAME=VALUE       set run-time parameter\n"));
     344           0 :     printf(_("  --describe-config  describe configuration parameters, then exit\n"));
     345           0 :     printf(_("  -?, --help         show this help, then exit\n"));
     346             : 
     347           0 :     printf(_("\nDeveloper options:\n"));
     348           0 :     printf(_("  -f s|i|o|b|t|n|m|h forbid use of some plan types\n"));
     349           0 :     printf(_("  -O                 allow system table structure changes\n"));
     350           0 :     printf(_("  -P                 disable system indexes\n"));
     351           0 :     printf(_("  -t pa|pl|ex        show timings after each query\n"));
     352           0 :     printf(_("  -T                 send SIGABRT to all backend processes if one dies\n"));
     353           0 :     printf(_("  -W NUM             wait NUM seconds to allow attach from a debugger\n"));
     354             : 
     355           0 :     printf(_("\nOptions for single-user mode:\n"));
     356           0 :     printf(_("  --single           selects single-user mode (must be first argument)\n"));
     357           0 :     printf(_("  DBNAME             database name (defaults to user name)\n"));
     358           0 :     printf(_("  -d 0-5             override debugging level\n"));
     359           0 :     printf(_("  -E                 echo statement before execution\n"));
     360           0 :     printf(_("  -j                 do not use newline as interactive query delimiter\n"));
     361           0 :     printf(_("  -r FILENAME        send stdout and stderr to given file\n"));
     362             : 
     363           0 :     printf(_("\nOptions for bootstrapping mode:\n"));
     364           0 :     printf(_("  --boot             selects bootstrapping mode (must be first argument)\n"));
     365           0 :     printf(_("  --check            selects check mode (must be first argument)\n"));
     366           0 :     printf(_("  DBNAME             database name (mandatory argument in bootstrapping mode)\n"));
     367           0 :     printf(_("  -r FILENAME        send stdout and stderr to given file\n"));
     368             : 
     369           0 :     printf(_("\nPlease read the documentation for the complete list of run-time\n"
     370             :              "configuration settings and how to set them on the command line or in\n"
     371             :              "the configuration file.\n\n"
     372             :              "Report bugs to <%s>.\n"), PACKAGE_BUGREPORT);
     373           0 :     printf(_("%s home page: <%s>\n"), PACKAGE_NAME, PACKAGE_URL);
     374           0 : }
     375             : 
     376             : 
     377             : 
     378             : static void
     379        1830 : check_root(const char *progname)
     380             : {
     381             : #ifndef WIN32
     382        1830 :     if (geteuid() == 0)
     383             :     {
     384           0 :         write_stderr("\"root\" execution of the PostgreSQL server is not permitted.\n"
     385             :                      "The server must be started under an unprivileged user ID to prevent\n"
     386             :                      "possible system security compromise.  See the documentation for\n"
     387             :                      "more information on how to properly start the server.\n");
     388           0 :         exit(1);
     389             :     }
     390             : 
     391             :     /*
     392             :      * Also make sure that real and effective uids are the same. Executing as
     393             :      * a setuid program from a root shell is a security hole, since on many
     394             :      * platforms a nefarious subroutine could setuid back to root if real uid
     395             :      * is root.  (Since nobody actually uses postgres as a setuid program,
     396             :      * trying to actively fix this situation seems more trouble than it's
     397             :      * worth; we'll just expend the effort to check for it.)
     398             :      */
     399        1830 :     if (getuid() != geteuid())
     400             :     {
     401           0 :         write_stderr("%s: real and effective user IDs must match\n",
     402             :                      progname);
     403           0 :         exit(1);
     404             :     }
     405             : #else                           /* WIN32 */
     406             :     if (pgwin32_is_admin())
     407             :     {
     408             :         write_stderr("Execution of PostgreSQL by a user with administrative permissions is not\n"
     409             :                      "permitted.\n"
     410             :                      "The server must be started under an unprivileged user ID to prevent\n"
     411             :                      "possible system security compromises.  See the documentation for\n"
     412             :                      "more information on how to properly start the server.\n");
     413             :         exit(1);
     414             :     }
     415             : #endif                          /* WIN32 */
     416        1830 : }
     417             : 
     418             : /*
     419             :  * At least on linux, set_ps_display() breaks /proc/$pid/environ. The
     420             :  * sanitizer library uses /proc/$pid/environ to implement getenv() as it wants
     421             :  * to work independent of libc. When just using undefined and alignment
     422             :  * sanitizers, the sanitizer library is only initialized when the first error
     423             :  * occurs, by which time we've often already called set_ps_display(),
     424             :  * preventing the sanitizer libraries from seeing the options.
     425             :  *
     426             :  * We can work around that by defining __ubsan_default_options, a weak symbol
     427             :  * libsanitizer uses to get defaults from the application, and return
     428             :  * getenv("UBSAN_OPTIONS"). But only if main already was reached, so that we
     429             :  * don't end up relying on a not-yet-working getenv().
     430             :  *
     431             :  * As this function won't get called when not running a sanitizer, it doesn't
     432             :  * seem necessary to only compile it conditionally.
     433             :  */
     434             : const char *__ubsan_default_options(void);
     435             : const char *
     436           0 : __ubsan_default_options(void)
     437             : {
     438             :     /* don't call libc before it's guaranteed to be initialized */
     439           0 :     if (!reached_main)
     440           0 :         return "";
     441             : 
     442           0 :     return getenv("UBSAN_OPTIONS");
     443             : }

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